1. Field of the Invention
The present invention relates to a locking device mounted on a bed of a truck or within an ambulance that carries sick or wounded people, and locks or fastens goods on the bed or a stretcher within the ambulance.
2. Description of the Related Art
The stretcher is generally used to transfer a sick or wounded person to the inside of an ambulance. After having been transferred into the ambulance, the stretcher is usually placed on a vibration isolator or the like and is then locked or fastened thereto by a locking device.
A ratchet mechanism is generally employed in the conventional locking devices for the stretchers. When the stretcher is locked, a hook is first raised and advanced, and is then locked by the ratchet mechanism. Conversely, when the stretcher is unlocked, a pawl is first released and the hook is then backed. Accordingly, the use of both hands is inevitably required, and not only is the operation troublesome, but also the locking and the unlocking can not be carried out rapidly.
Furthermore, although various locking devices for locking goods on the bed of a truck have been proposed up to this time, many of them have only a small versatility or flexibility and, hence, cannot be used to lock the stretcher or other machines or apparatuses.
The present invention has been developed to overcome the above-described disadvantages.
It is accordingly an objective of the present invention to provide a reliable general-purpose locking device whereby locking and unlocking can be readily and rapidly performed using only one hand.
In accomplishing the above and other objectives, the locking device according to the present invention includes a frame, an operating handle rotatably mounted on the frame, a link mechanism connected to the operating handle and having a recess defined therein, a hook connected to the operating handle via the link mechanism, and a locking pin slidable relative to the operating handle. With this arrangement, the hook is locked by introducing the locking pin into the recess and is unlocked by moving the locking pin apart from the recess, making it possible to perform locking and unlocking rapidly with simple operation.
Advantageously, the locking device further includes a lock releasing handle slidable relative to the operating handle, wherein the locking pin is secured to the lock releasing handle. By this construction, the locking and unlocking can be readily performed using only one hand.
Conveniently, the operating handle and the lock releasing handle have respective grips disposed adjacent and extending substantially parallel to each other. By this construction, the locking can be rapidly released merely by grasping both the grips.
Preferably, the locking device further includes an elastic member for biasing the lock releasing handle. The hook is locked by the elastic member that biases the lock releasing handle in a direction in which the grip of the lock releasing handle is moved away from the grip of the operating handle, while the hook is unlocked by moving the grip of the lock releasing handle towards the grip of the operating handle against an elastic force of the elastic member. By so doing, not only can the hook be rapidly released merely by grasping both the grips, but the hook can also be readily locked by means of the biasing force of the elastic member when the user takes his hand off the grips.
The locking device according to the present invention is mounted on, for example, a vibration isolator for a stretcher. In this case, the position of the locking device can be adjusted in a direction longitudinally of the vibration isolator, making it possible to absorb variations in the vibration isolator and to provide a reliable locking device.
In another form of the present invention, a locking device includes a frame, an operating handle rotatably mounted on the frame, a link mechanism connected to the operating handle, a hook connected to the operating handle via the link mechanism and being movable between a locking position and a lock-released position, and an eccentric cam connected to the link mechanism. A center of rotation of the hook at the locking position is moved below the center of rotation of the hook at the lock-released position by rotating the eccentric cam via the link mechanism, making it possible to positively perform the locking.
Advantageously, the locking device further includes a rocking shaft connected to the operating handle via the link mechanism. The hook has an elongated opening defined therein in which the rocking shaft is loosely inserted. By this construction, the hook can be rapidly moved towards the locking position.
The locking device further includes a locking pin slidable relative to the operating handle. The link mechanism includes an arm having a recess defined therein, and the hook is locked by introducing the locking pin into the recess and is unlocked by moving the locking pin apart from the recess, making it possible to perform locking and unlocking rapidly with simple operation.
The locking device also includes an elastic member connected to the hook. An elastic force of the elastic member acts on the hook in a first direction when the hook is at the locking position, while the elastic force of the elastic member acts on the hook in a second direction counter to the first direction when the hook is at the lock-released position. By so doing, not only can the locking and unlocking be performed rapidly, but the hook can also be positively held at the locking position or at the lock-released position.